1. Field of the Invention
This invention relates to the field of automobile service lifts, and in particular to a lift having adjustable outriggers which can compensate for deflection of the outriggers due to the weight of a vehicle on the lift.
2. Description of the Related Art
A wide variety of post-type automobile lifts have been previously known and used in the automobile repair business to provide access to the underside of a vehicle. Post lifts can be either of the in-ground or above-ground variety. In-ground post lifts usually have one or two vertically ascending columns mounted below the floor of a garage or service area which are raised hydraulically to lift the vehicle. Above-ground post lifts generally have two or four vertical columns or “posts,” each of which includes a carriage which rides up and down the post. These carriages are often raised and lowered by means of a chain, cable, or other flexible lifting member which is driven by a winch or hydraulic actuator.
Each carriage has one or more arms or “outriggers” which extend outwardly from the carriage. On some lifts, the outriggers directly engage the undercarriage of a vehicle such that the wheels of the vehicle are unsupported after the vehicle is lifted. On other lifts (which are typically four post lifts) the outriggers of the two posts on each side of the lift support a platform or “runway” which supports the wheels of the vehicle. Lifts of this second type are often used for wheel alignment work because this type of maintenance requires that the wheels be supported and not hanging freely. Alignment lifts may include rotatable turntables mounted to the runways under the front wheels of the vehicle. These turntables allow the front wheels to be easily turned during the alignment process.
A problem with existing post-type lifts is that the outriggers can sag when a load is applied to them. This can cause the runways to become out of level. This problem is particularly detrimental when doing alignment work because the vehicle must be level for the adjustments to be made accurately. What is needed is a lift which allows the outriggers to be leveled to compensate for deflection due to the weight of the vehicle.